[A-HW23] Isotope Hydrology 2021

[AHW23-P05] Numerical modeling on the spatial distribution of d-excess values in river water in Japan

*Masaaki Takahashi¹, Hinako Shimizu¹, Akihiko Inamura¹, Noritoshi Morikawa¹ (1.The National Institute of Advanced Industrial Science and Technology)

Keywords:river water, d-excess value, spatial distribution, numerical modeling

There are many studies on the spatial distribution of δD and δ¹⁸O values in river water in Japan, and numerical modeling are also shown. Latitude, altitude, annual mean temperature, distance from the coastline, precipitation amount, etc. are used as topographical and geographical parameters. On the other hand, there are many studies on the spatial distribution of d-excess values (δD–8xδ¹⁸O) in river water, such as Katsuyama et al. (2015), but no numerical modeling has been shown, yet. From previous studies on the spatial distribution of d-excess values in river water, it is clarified that it does not depend on latitude, altitude, distance from the coastline, etc., and is also recognized that d-excess values change extremely at the (central) watershed.

This study presents the effect of "summer" and "winter" precipitation amounts on the spatial distribution of d-excess values in river water.